Curing rim

ABSTRACT

A method and apparatus for use in curing vehicle tires including a tire support rim possessing a first inlet to introduce an initial pressure into an inner tube to seat a tire on the rim. The curing rim further includes a second inlet for introducing a second pressure between the inner tube and the casing of the vehicle tire to deflate the inner tube and maintain the vehicle tire in proper position during a curing operation.

BACKGROUND OF THE INVENTION

This invention relates in general to vehicle tires and in particular, toa method and apparatus to be used in conjunction with curing of vehicletires.

More specifically, the invention relates to a method and apparatus inwhich a curing rim having an improved static seal is utilized to supporta vehicle tire during a curing operation. The improved curing rim of theinvention includes means to introduce an initial pressure to an innertube to expand a tire into seating relationship on the rim whereby therim includes means to apply a greater pressure to the exterior of theinner tube to deflate the inner tube and apply a pressure to the tire tomaintain it in position during a curing operation. The rim of theinvention further includes adjustable means accommodating variable widthspacers to permit the rim of the invention to be utilized with tireshaving a variety of widths.

It is a common process in the prior art to cure vehicle tires whichmethod encompasses the buffing and retreading of used tires in aconventional mold under elevated heat conditions. During a curingoperation, the vehicle tire is generally maintained on a curing rimwhereby an inner tube within the tire is pressurized to such an extentthat the tire is maintained in a pressurized condition to permit properretreading, buffing and the like. However, the use of an inner tube tomaintain proper bias of a vehicle tire during curing presents severaldisadvantages, particularly in conjunction with the use of very largevehicle tires such as found in land moving equipment and the like.

It has been found that often inner tubes pressurized to support a tireoften burst during curing. When such failure occurs, the curingoperation of a tire is seriously interferred with and improper curingmost likely occurs. Moreover, the inner tube utilized to support largevehicle tires are relatively costly and it becomes very expensive toconstantly have to replace these items. Thus, the failure of an innertube within a tire during a curing operation produces seriousdetrimental results. For these reasons, it is desirable to provide animproved method and apparatus for supporting a vehicle tire duringcuring in which the aforementioned problems are alleviated.

SUMMARY OF THE INVENTION

It is, therefore, an object of this invention to improve the curing ofvehicle tires.

A further object of this invention is to eliminate the necessity ofutilizing an inner tube to maintain a vehicle tire in position during acuring operation.

Another object of this invention is to apply high pressure between theexterior of an inner tube and the tire casing to maintain the tire inthe proper position during curing.

It is still another object of this invention to provide an curing rimhaving an improved static seal to achieve a more efficient and effectivecuring operation.

These and other objects are attained in accordance with the presentinvention wherein there is provided a support rim for supporting avehicle tire during curing and having an improved static seal to permitan inner tube to be initially inflated to a predetermined pressure forseating the vehicle tire on the rim. The rim further includes means forthereafter applying a higher level of pressure between the tire casingand the inner tube for exhausting the pressure in the tube and biasingthe tire in position with proper stiffness during a curing operation.

The improved support rim of the invention overcomes the aforementionedproblems of the prior art by extending the lifetime of use of an innertube and by eliminating the necessity of using the inner tube tomaintain pressure against the vehicle tire during curing. Thus, thecuring rim of the invention permits the vehicle tire to be moreeffectively maintained in position without the disadvantages of theprior art of having inner tubes burst and disrupt the entire curingprocess of a tire. The rim of the invention further is capable ofhandling a wide range of various widths of tires by a simplified andeffective technique.

BRIEF DESCRIPTION OF THE DRAWINGS

Further objects of this invention, together with additional featurescontributing thereto and advantages accuring therefrom, will be apparentfrom the following description of embodiments of the invention when readin conjunction with the accompanying drawings:

FIG. 1 is a cross sectional view of the curing rim of the inventionhaving a tire to be cured mounted thereon and being supported forseating by an inflated inner tube;

FIG. 2 is a partial cross sectional view of the curing rim of FIG. 1illustrating the condition of the tire after the application of pressurebetween the tire interior and the tube; and

FIG. 3 is an enlarged partial sectional view of a spacer for varying thewidth of the curing rim of the invention.

DESCRIPTION OF A PREFERRED EMBODIMENT

Referring now in particular to FIG. 1 there is illustrated the improvedrim of the invention supporting a vehicle tire, particularly as used inconjunction with the conventional curing operation. The body of curingrim 1 is formed from a pair of substantially identical cylindricalsleeves 2 and 3 of any suitable strong material such as metal. Sleeve 2includes a ring 4 permanently affixed to its interior surface and sleeve3 includes a ring 5 affixed to its interior surface whereby in an end toend relation of sleeves 2 and 3, a respective face of rings 5 and 6substantially confront each other. Sleeves 2 and 3 are affixed in an endto end relation by means of bolts 6 which pass through suitable holes inrings 4 and 5.

Bolts 6 can be of a suitable member and generally are positionedcircumferentially around rings 4 and 5. In order to maintain a staticseal at the point of end to end connection of rings 2 and 3, aconventional O-ring 6' is positioned within ring 4 around its circularextent and permits pressurization of a tire mounted on rim 1. Rimflanges 7 and 8 are integrally attached to sleeves 2 and 3 and aredisposed on opposite sides of the curing rim and extendcircumferentially around the rim for bearing contact with the bead of avehicle tire.

Still referring to FIG. 1, a tire 10 being mounted on curing rim 1 isshown and includes a conventional bead which when pressure is applied tothe interior of the tire will seat against flanges 7 and 8 in a sealingrelationship. An inner tube 20 of any suitable inflatable material suchas rubber is adapted to be positioned within tire 10. In FIG. 1 innertube 20 is in an inflated condition to force tire bead 11 against rimflanges 7 and 8. To cause such seating of the tire bead, air isintroduced through tube stem 21 extending through an inlet 22 formed insleeve 3. It has been found that seating of a tire can be achieved inthe present invention by a pressure of approximately 30 pounds persquare inch. However, the pressure necessary to seat the bead in sealedrelationship on the rim can be of variable magnitudes dependant on suchfactors as tire size, material and the like.

Referring to FIG. 2 there is illustrated the condition of inner tube 20within the tire during the actual curing operation. The pneumaticpressure initially introduced into the inner tube 20 to seat bead 11 isdischarged from the tube through stem 21 by the application of a higherpressure between the casing of the tire 10 and the exterior of the innertube 20 in area 30. Such a pneumatic pressure can be applied from anyconventional pressure source through an inlet 31 within one of thesleeves 3 and 4 whereby a pressure up to 225 p.s.i. can be forcedbetween the outside of the tube and the inside of the tire. Such apressure will cause the collapse of the inner tube since the originalpressure for seating bead 11 escapes through stem 21. It should be notedthat the tube stem 21 may be secured to any suitable means such as stemclamp 23 attached to inlet 22 and thus remains in position therethroughdespite collapsing of the tube. Stem clamp 23 comprises a cylindricaltube having a passage 23' and a washer 24 attached at one end. Tube stem21 includes a threaded end 21' which is attached to internal threads 25.The end clamp 23 includes threads 26 which attach to a pneumaticpressure source. As shown in FIG. 1 a face of washer 24 contacts sleeve3 adjacent hole 22 in sealed relationship. The pressure exiting throughtube stem 21 during application of the second pressure can be directedto the atmosphere or a collection manifold (not shown) and the like assuitable.

Although the invention is not intended to be so limited, a plug (notshown) can be attached to stem 21 after the original pressure isintroduced into tube 20 to maintain the pressure within the tube toinsure seating of bead 11 if necessary under certain circumstances. Sucha plug can be removed prior to or simultaneous with the application ofcuring pressure through inlet 31 to permit proper exhausting from tube20. Alternatively, pressure may also sequentially applied through stem21 and inlet 31 by use of a suitable valving mechanism (not shown)permitting both pressurization and exhausting in accordance with theforegoing description of the invention.

In view of the fact that the stem 21 is retained in inlet 22 afterdischarge, tube 20 most likely hangs in approximately the position shownin FIG. 3. The application of pressure into area 30 of the tire 10 issufficient to maintain the tire in proper position during a curingoperation and alleviates completely the problem of a stress beingapplied to the inner tube. It should be apparent that rim 1 maintainsthe tire in a sealed pressurized relationship during the curing process.

Referring to FIG. 3 there is illustrated a spacer element which permitsthe curing rim of the invention to accommodate tires of varying widthshaving a common diameter. Such accommodation for varying widths of thetires is accomplished by the use of spacer 40 as illustrated in FIG. 3.Spacer 40 can be of any predetermined width dependent on the size of atire to be cured. Spacer 40 is constructed of a suitably hard materialto adequately seal the pressure within the tire even during highpressurization and is situated between ends of sleeves 2 and 3 andbetween the corresponding faces of rings 5 and 6. One side of spacer 40is sealed by means of O-ring 6' provided in ring 4 and at the other sideis sealed by a circular O-ring 41 positioned within a groove 42 formedin the end of spacer 40. Sleeves 4 and 5 and spacer 40 are retainedtogether by means of a series of circumferentially arranged bolts 6a,passing through rings 4 and 5 and spacer 40. It should be apparent toone skilled in the art that the length of bolts 6a used in conjunctionwith the spacer 40 depends on the selected width of spacer 40.

In operation of the curing rim of the invention as described in theforegoing description, a vehicle tire to be cured having an inner tubetherein is positioned upon the curing rim and a pressure sufficient toinflate the inner tube 20 is introduced through inlet 21 whereby thebead 11 of tire 10 is seated against flanges 7 and 8. After seating ofthe tire against the flanges, pressure from a suitable pneumatic sourceis introduced through inlet 31 between the exterior of the inner tube 20and the interior of the tire casing so that the pressure within theinner tube is discharged through inlet 21. A pressure of up to 225p.s.i. or other appropriate magnitude effectively maintains the tireproperly in position during the curing operation.

While the invention has been described with reference to a preferredembodiment, it will be understood by those skilled in the art thatvarious changes may be made and equivalents may be substituted forelements thereof without departing from the scope of the invention. Inaddition, many modifications may be made to adapt a particular situationor material to the teachings of the invention without departing from theessential scope thereof. Therefore, it is intended that this inventionnot be limited to the particular embodiment disclosed as the best modecontemplated for carrying out this invention, but that the inventionwill include all embodiments falling within the scope of the appendedclaims.

What is claimed is: .[.
 1. A rim for supporting a vehicle tire during acuring operation comprising:a pair of sleeves adapted to be secured inan end to end relationship; said sleeves including attachment means tosecure said sleeves for support of a vehicle tire during a curingoperation; sealing means operatively coupled to said sleeves to retain avehicle tire in sealed relation on the periphery of said sleeves; one ofsaid sleeves including an inlet opening therein for receiving said stemof an inner tube within a vehicle tire; and said one of said sleevesfurther including a second inlet therein defining means applying apressurized fluid between the interior of a vehicle tire and theexterior of an inner tube..]. .[.2. The rim of claim 1 furthercomprising spacer means adapted to be connected to said attachment meansto vary the width of sleeves to accommodate vehicle tires of selectedwidth..]. .[.3. The rim of claim 1 wherein said attachment meansincludes a pair of rings respectively affixed to the inner periphery ofsaid sleeves..]. .[.4. The rim of claim 3 wherein said attachment meansfurther includes bolt means adapted to pass through said rings to securesaid sleeves in an end to end relationship..]. .[.5. The rim of claim 4wherein said sleeves respectively include a flange positioned atopposite end thereof on the periphery of said sleeves..]. .[.6. A rimfor supporting a vehicle tire during a curing operation comprising: bodymeans for supporting a vehicle tire in a sealed relation thereon; saidbody means having a first inlet means for introducing pressure into aninner tube positioned within a vehicle tire; and said body means furtherincluding a second inlet opening for introducing pressure into said tirebetween said inner tube and the interior of the vehicle tire..].
 7. Amethod of supporting a vehicle tire during a curing operation comprisingthe steps of:mounting a vehicle tire having an inner tube on theperiphery of a rim; introducing a predetermined pressure into said innertube for inflation thereof for seating the bead of the vehicle tire insealed relationship on the rim; and introducing pressure greater thansaid predetermined pressure into said vehicle tire between the interiorof the tire and the outer periphery of the inner tube to exhaust saidpredetermined pressure from the inner tube and bias said tire inposition during a curing operation.
 8. The method of claim 7 whereinsaid predetermined pressure is of a magnitude of up to 30 pounds persquare inch.
 9. The method of claim 8 wherein said pressure greater thansaid predetermined pressure is of a magnitude of up to 225 pounds persquare inch.